Back in the autumn of 1998 O'Brien leapt from one foxhole, the Sunday Independent, into another, my newspaper The Observer which he once edited, hurling dangerous and explosive ideas across the battlefield.

O'Brien had spent the winter and spring of '98 opposing David Trimble's decision to persuade most of unionism to back a peace deal culminating in the Good Friday Agreement. Much to the bewilderment of many of his admirers, the former diplomat, Irish Cabinet minister and writer had joined Bob McCartney's integrationist UK Unionist Party.

Yet within months of standing on platforms not only with McCartney (one of his heroes in later life) but also Ian Paisley, denouncing any settlement that would bring Sinn Fein in from the cold, he proposed that unionists should become ex-unionists and embrace a United Ireland.

One of the Provisional IRA's most vocal opponents in the Republic allowed The Observer and the Sunday Independent to publish controversial extracts from his final memoir in which he urged unionists to look south rather than east. O'Brien suggested the unionists or rather an ex-unionist political bloc would be able to exercise more influence in the Dail than in Westminster or for that matter a devolved northern parliament.

Unionists would in fact, he contended, be permanent “king makers” given that their votes in the Irish parliament would be critical and they could exact a greater, more fruitful price for supporting either Fine Gael or Fianna Fail in forming governments.

Conversely, if the southern political establishment baulked at such an offer from the unionist political representatives, worried no doubt that they (FG or FF and maybe their Labour or Green crutches) would have to constantly appease this northern electoral force, then it would shatter the myth forever that all parties south of the border were driven by a burning desire for Irish unity.

Even if most unionists in turn would, and most certainly did back in 1998, recoil from O'Brien's radical proposal they could still learn a thing or two about canny political strategic thinking from their deceased former southern ally.

The Republic's Constitutional Convention, which is currently reviewing the way the state is run and coming up with various reform proposals to transform it, has backed the idea of northerners voting in Presidential elections. The move must be music to Sinn Fein ears because the additional tens of thousands of their supporters in Northern Ireland in a vote for the next President of the Republic would have, perhaps, pushed Martin McGuinness lahead of Michael D Higgins last time and elected the former IRA chief of staff to chief of staff of the Irish Defence Forces.

If, as seems likely, northern Irish passport holders are granted the vote next time around, then would for example their numbers be enough to elect Gerry Adams and place the former barman from Ballymurphy into the presidential residence in Dublin's Phoenix Park?

Ironically the only ones that might be able to stop Adams becoming head of state (outside of those at the centre of the Liam Adams abuse scandal and Gerry's silence for years about it) are the unionists.

This time around they do not have to re-constitute themselves as ex-unionists. Instead they have two routes they could follow in the O'Brien tradition of thinking outside the box. Firstly, they could in their thousands apply for Irish passports as is their right under the Good Friday Agreement. Then just like their nationalist neighbours up north they too could have the automatic right to determine who is the Republic's next Head of State, only in this next election they would be able to choose the strongest alternative to stop say Gerry Adams. It is not such an outlandish notion given that many unionists already hold Irish passports including at least one senior loyalist paramilitary for reasons of pragmatic travel arrangements.

However, even if they were repelled by the thought of starting a mass campaign for unionist voters to apply to the Irish passport office in Dublin, the main unionist parties could still demand the right to vote. The DUP and UUP could argue that their voters don't need Irish passports because under the Good Friday Agreement everyone in theory is an Irish citizen since Easter 1998. They could demand the right to vote like everyone else north of the border in a Presidential election and argue that otherwise they are being discriminated against by the southern nationalist establishment. Knowing the deep enmity that runs within not only Fine Gael but also Fianna Fail to Sinn Fein's plans for Adams to be crowned head of state as a reward for a lifetime of “struggle”, you wonder how much resistance the main parties in Dublin would put up to prevent unionists from having the right to vote too!

All this of course is based on an assumption that unionism can still think strategically rather than viscerally about, in this scenario at least, how important southern politics might just be to their survival in the future. Rather than wasting time at “civil rights camps” on the Woodvale Road or numerically diminishing protests over flags outside Belfast City Hall, a trip to Dublin to discuss how unionist voters could play a decisive part in future Irish Presidential elections would be far more politically valuable in the long run.

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